1. Technical Field
The present invention relates to lens modules, and particularly to a lens module with an auto focus mechanism.
2. Description of Related Art
With the ongoing development of microcircuitry and multimedia technology, camera modules, including, e.g., still camera modules and digital camera modules are now in widespread use and are being combined with various electronic devices. Such camera modules need to be cheap and to have excellent optical characteristics.
A camera module of the related art includes at least one lens module and an image sensor module in alignment with the at least one lens module. The at least one lens module typically includes a lens barrel and lenses assembled in the lens barrel. Recently, lens modules have begun to integrate auto focus mechanisms, such as step motors for driving the lenses to move relative to the image sensor module, thereby achieving the auto focus function. However, the step motor is relatively bulky in volume. In addition, the step motor consumes a substantial amount of power, especially relative to the amount of power that can be stored in a typical battery system of a camera or an electronic device.
What is needed, therefore, is a lens module which has a simple and energy-efficient auto focus mechanism.